Article

Grapes(Chk1) prevents nuclear CDK1 activation by delaying cyclin B nuclear accumulation

Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.
The Journal of Cell Biology (Impact Factor: 9.69). 11/2008; 183(1):63-75. DOI: 10.1083/jcb.200801153
Source: PubMed

ABSTRACT Entry into mitosis is characterized by a dramatic remodeling of nuclear and cytoplasmic compartments. These changes are driven by cyclin-dependent kinase 1 (CDK1) activity, yet how cytoplasmic and nuclear CDK1 activities are coordinated is unclear. We injected cyclin B (CycB) into Drosophila melanogaster embryos during interphase of syncytial cycles and monitored effects on cytoplasmic and nuclear mitotic events. In untreated embryos or embryos arrested in interphase with a protein synthesis inhibitor, injection of CycB accelerates nuclear envelope breakdown and mitotic remodeling of the cytoskeleton. Upon activation of the Grapes(checkpoint kinase 1) (Grp(Chk1))-dependent S-phase checkpoint, increased levels of CycB drives cytoplasmic but not nuclear mitotic events. Grp(Chk1) prevents nuclear CDK1 activation by delaying CycB nuclear accumulation through Wee1-dependent and independent mechanisms.

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